Supporting structure for adjustable air guide vanes

ABSTRACT

A structure for supporting an air guide vane in a supply opening for air conditioning prevents abrupt changes of load resistance to rotation of the air guide van and provides a good operational feel when rotating the air guide vane. A supporting member of the air guide vane is an olefin-based thermoplastic elastomer having a hardness of between Shore A80 and Shore D60. The degree of mold transferability of olefin-based thermoplastic elastomer is characteristically lower than that of other thermoplastic elastomers. By virtue of molding an olefin-based thermoplastic elastomer microscopic concavities and convexities are formed on the surface of the supporting member. The rotation shaft of the air guide vane is supported by multiple point contacts with the inner surface respective through-holes.

FIELD OF THE INVENTION

The present invention relates to a structure for supporting an air guide vane in a supply opening for air conditioning in vehicles, especially relates to a structure for supporting an adjustable air guide vane.

DESCRIPTION OF THE RELATED ART

An apparatus for changing the direction of airflow from a supply opening for air conditioning, which comprises a plurality of vanes for changing the direction of airflow from an air-conditioning duct and a manual operation knob handled by a vehicle driver to change the direction of the vanes, has been suggested in the past. For example, Japanese Patent Public Disclosure No. H10-250357 discloses a wind direction adjusting device that is designed to prevent deterioration of an outside appearance due to use of an operation knob, and to make it possible to reduce the control force for sliding the operation knob, and the rest.

In such an apparatus, wind direction is adjusted by a vehicle driver who manually operates a knob to rotate louvers or vanes. Therefore, the operational feeling of the operation knob is affected not only by the slidability of the operation knob but also by the rotational friction force of the louvers or vanes. The air blowing-out port device for vehicle, which is disclosed in Japanese Patent Public Disclosure No. H08-145455, comprises a generally square-shaped shim of elastic materials such as rubber and elastomer that support a lower shaft part of a central vertical blade. Alternatively, a blade connecting member made of elastomer can be substituted for the shim in the air blowing-out port device for vehicle.

If a machine part is molded by injecting polyester-based thermoplastic elastomer into ordinary molding dies, irregular concavities and convexities of the die surfaces are transferred to the surfaces of the molded part, and extremely irregular concavities and convexities of relatively large size are formed on the surfaces of the molded part as shown in FIG. 7 in the drawings. As a result, when another part is slid along the surface of the molded part, an abrupt load change is caused at peaks P1 and P2 of a load curve R1 in FIG. 9 in the drawings. Consequently, if the rotation shaft of a vane is borne by the molded part having the aforementioned rough surface, the operational feeling of the vane becomes worse and the rotational movement of the vane becomes unstable. In addition, the molded part for supporting the vane tends to suffer wear or uneven abrasion due to repeated rotation of the vane. Since a required torque to rotate the vane varies as the molded part is worn away, it becomes more difficult to retain the predetermined operational feeling of the vane for a long period of time. Furthermore, in order to eliminate the irregular concavities and convexities on a working surface of a molding die and produce a flat and smooth working surface that does not impair the function of a molded part, the working surface of a molding die should be processed by an expensive treatment as a general rule.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a structure for supporting air guide vanes in a supply opening for air conditioning, which can produce a stable load resistance to rotation of the air guide vane when rotating the air guide vane, so that a good operational feeling of rotation of the air guide vane can be obtained.

Another objective of the present invention is to provide a structure for supporting an air guide vane in a supply opening for air conditioning, which can prevent causing abrupt changes in the load resistance to rotation of the air guide vane, so that a good operational feeling of rotation of the air guide vane can be obtained.

Further objective of the present invention is to provide a structure for supporting an air guide vane in a supply opening for air conditioning, which can maintain a virtually constant operational feeling of rotation of the air guide vane even if the rotation of the air guide vane is repeated.

Further objective of the present invention is to provide a structure for supporting an air guide vane in a supply opening for air conditioning, which can bring the rotation of the air guide vanes to a halt at a desired angle and hold the air guide vane at the angular position.

Further objective of the present invention is to provide a structure for supporting an air guide vane in a supply opening of air conditioning, which can obviate the needs for processing an expensive treatment to the working surface of a molding die and reduce the costs of manufacturing the supporting structure.

The structure for supporting air guide vanes in a supply opening for air conditioning according to the present invention comprises: air guide vanes disposed in a supply opening for air conditioning and adapted to change the direction of airflow by manual rotation of the air guide vanes, and a supporting member comprising bearing surfaces for supporting the air guide vanes rotatably and a lot of microscopic concavities and convexities formed on the bearing surfaces in order to control the load resistance to rotation of the air guide vanes. A lot of microscopic concavities and convexities are formed in order that the peak value of the load resistance to rotation of the air guide vanes is maintained at a virtually constant value. In addition, a lot of microscopic concavities and convexities are formed in order that the load resistance to rotation of the air guide vanes does not represent drastic load changes at the time of the peak values thereof.

Another aspect of the structure for supporting air guide vanes in a supply opening for air conditioning according to the present invention comprises: a rotation shaft formed on the end faces of the air guide vanes; a hole or bore formed in the supporting member to receive the rotation shaft; and a lot of microscopic concavities and convexities formed on the inner surface of the hole or bore; wherein the rotation shaft is supported by multiple point contacts with the inner surface of the respective hole or bore.

The structure for supporting air guide vanes in a supply opening for air conditioning according to the present invention is also characterized in that the rotation shafts of the air guide vanes each are formed by a circular column-shaped boss; and the supporting member is provided with the holes or bores into which the circular column-shaped boss is rotatably inserted; and the bearing surface for supporting the circular column-shaped boss is formed by the inner surface of each of the holes or bores.

In addition, the structure for supporting air guide vanes according to the present invention preferably comprises: the supporting member that is manufactured by molding olefin-based thermoplastic elastomer molded in a molding die; and a lot of microscopic concavities and convexities formed at least on the bearing surface that supports the air guide vanes rotatably. Furthermore, the olefin-based thermoplastic elastomer preferably has a hardness of between Shore A80 and Shore D60.

In another embodiment of the structure for supporting air guide vanes according to the present invention, a circular column-shaped boss is formed in the outer and inner end faces of the air guide vanes, respectively, to form the rotation shafts of the air guide vanes. A supporting member is provided with holes or bores into which the circular column-shaped bosses are rotatably inserted. A bearing surface for supporting the circular column-shaped boss is defined by the inner surface of the hole or bore. One of the circular column-shaped bosses of each of the air guide vanes is rotatably inserted into the hole or bore of the supporting member. Simultaneously, the other of the circular column-shaped bosses of the air guide vane can be supported to turn freely in order to avoid varying the torque to rotate said air guide vane when rotating the air guide vanes.

In a further embodiment of the structure for supporting air guide vanes according to the present invention, an air guide vane consists of a plurality of air guide vanes that are arranged to leave a predetermined space between adjacent air guide vanes and to extend in parallel with one another. A plurality of holes or bores are formed at predetermined intervals in the supporting member. One of the circular column-shaped bosses of each of the air guide vanes is inserted into the respective holes or bores. The air guide vanes are connected by a link member to rotate in conjunction with one another. And an operation knob is attached to one of the air guide vanes.

The structure for supporting air guide vanes according to the present invention may comprise: a plurality of air guide vanes arranged on the both sides of the supporting member; a plurality of through-holes or through-bores formed at predetermined intervals in the supporting member; and circular column-shaped bosses formed on the inner end faces of the air guide vanes, wherein the circular column-shaped bosses are rotatably inserted into the respective through-holes or through-bores from the both sides of the supporting member.

The supporting member of the air guide vanes according to the present invention preferably consists of olefin-based thermoplastic elastomer having a hardness of between Shore A80 and Shore D60. The hardness of the bearing surface of the supporting member can be set to an appropriate degree of hardness. Consequently, it becomes possible to provide a stable load resistance to rotation of air guide vanes and obtain a good operational feeling of rotation of the air guide vane. Since the degree of mold transferability of olefin-based thermoplastic elastomer is characteristically lower than that of other thermoplastic elastomer, a lot of microscopic concavities and convexities can be formed on the bearing surface regardless of how the working surface of the mold is processed.

The bearing surface on which a lot of microscopic concavities and convexities are virtually uniformly formed according to the present invention is hardly affected by a fine abrasion powder. Therefore, the amount of torque required to rotate air guide vanes hardly varies even if the air guide vanes are turned repeatedly. Consequently, the virtually constant operational feeling in rotating the air guide vanes can be maintained during long-term use.

In addition, if the structure for supporting air guide vanes according to the present invention comprises a supporting member made of olefin-based thermoplastic elastomer having a hardness of between Shore A80 and Shore D60, and a bearing surface formed on the supporting member to bear the rotation shafts of the air guide vanes, the hardness of the bearing surface can be set appropriately. Since a lot of microscopic concavities and convexities are formed on the bearing surface virtually uniformly, a substantially constant load resistance to rotation can be applied to the air guide vanes. Consequently, it is possible to bring the rotation of the air guide vanes to a halt at a desired angle and hold the air guide vane at the angular position.

The structure for supporting air guide vanes in a supply opening for air conditioning according to the present invention can be manufactured inexpensively because it is not necessary to process an expensive treatment to the working surfaces of molding dies.

These and other features of the present invention will be defined from the following description of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of supply openings for air conditioning in a vehicle, which comprises an apparatus for changing the direction of airflow in which a structure for supporting air guide vanes in a supply opening according to the present invention is installed;

FIG. 2 shows a vertical cross-sectional view taken along a line II-II in FIG. 1;

FIG. 3 shows a perspective view of the structure for supporting air guide vanes according to the present invention;

FIG. 4 shows a transverse cross-sectional view taken along a line IV-IV in FIG. 1;

FIG. 5 shows an enlarged section in the vicinity of a supporting member in FIG. 4;

FIG. 6 shows an exploded perspective view of an operation knob, an elastic member and an air guide vane;

FIG. 7 is a micrograph showing a 500 times magnification of the surface of the part that is formed by injecting a conventional polyester-based thermoplastic elastomer into a conventional molds;

FIG. 8 is a micrograph showing a 500 times magnification of the surface of the supporting member that is molded by injecting olefin-based thermoplastic elastomer according to the present invention;

FIG. 9 is a diagram showing a load resistance to rotation of an air guide vane that is borne by the conventional supporting member having the surface of FIG. 7; and

FIG. 10 is a diagram showing a load resistance to rotation of an air guide vane that is borne by the supporting member having the surface of FIG. 8 according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-6 illustrate an embodiment of the present invention wherein the supporting structure for adjustable air guide vanes according to the present invention is embodied in an apparatus for changing the direction of airflow, which is disposed in a supply opening for air conditioning, and the supply opening opens into a vehicle interior. An opening 3 is formed in a panel portion 2 defined at the end of an air-conditioning duct 1 and a supporting member 4 is attached to the central portion of the opening 3. A cover member 4 a is fitted on the front surface of the supporting member 4 and by the supporting member 4 and the cover member 4 a, the opening 3 is divided into two supply openings 3 a, 3 b for air conditioning. As illustrated in FIGS. 2 and 5, the supporting member 4 is connected to a partition wall 5 by which two passages 1 a, 1 b are defined in the air-conditioning duct 1. The supply opening 3 a is communicated with the passage 1 a, while the supply opening 3 b is communicated with the passage 1 b.

An apparatus for changing the direction of airflow 6 is installed in the supply opening 3 a that is communicated with the passage 1 a and in the supply opening 3 b that is communicated with the passage 1 b. Air guide vanes 7 a, 7 b, 7 c, 7 d of each of the airflow-direction changing apparatus 6 extend horizontally, while rotational vanes 8 a, 8 b, 8 c, 8 d, 8 e that are disposed on the upstream side of the air guide vanes 7 a, 7 b, 7 c, 7 d extend vertically.

As illustrated in FIGS. 1 to 3, the air guide vanes 7 a-7 d of each of the airflow-direction changing apparatus 6 are aligned to leave a regular space between adjacent vanes and arranged in parallel to one another. As illustrated in FIGS. 2 to 6, a rotation shaft 9 a is formed on the outside end faces of the air guide vanes 7 a-7 d extending in the wingspan direction B-B and a rotation shaft 9 b is formed on the inside end faces of the air guide vanes 7 a-7 d extending in the wingspan direction B-B. The rotation shafts 9 a, 9 b are formed in a circular column-like shape and horizontally project from the outside and inside end faces of the air guide vanes 7 a-7 d in the wingspan direction B-B.

As illustrated in FIG. 4, the rotation shafts 9 a of the air guide vanes 7 a-7 d are inserted into the respective four holes 2 a in the panel portion 2 and supported to revolve freely. The holes 2 a are formed in the panel portion 2 to align in the vertical direction and leave space between adjacent holes, so as to receive the respective rotation shafts 9 a of the air guide vanes 7 a-7 d. As illustrated in FIGS. 4 and 5, the rotation shafts 9 b of the air guide vanes 7 a-7 d are inserted into the respective four through-holes 4 b in the supporting member 4 and supported to be rotatable. The through-holes 9 b are formed in the supporting member 4 to align in the vertical direction and leave space between adjacent through-holes, so as to receive the rotation shafts 9 b of the air guide vanes 7 a-7 d. The through-holes 9 b each run through the supporting member 4 and open in the both sides of the supporting member 4. The through-holes 4 b are formed on the sides of the supporting member 4 to align in the vertical direction and leave space between adjacent through-holes, so that the through-holes 4 b are opposed to the corresponding holes 2 a, respectively. As illustrated in FIG. 4, the rotation shafts 9 b of the air guide vanes 7 a-7 d disposed in the supply openings 3 a and 3 b are inserted into the four through-holes 4 b from the respective sides of the supporting member 4. And the inner surfaces of the through-holes 4 b serve as a bearing surface for rotatably supporting the rotation shafts 9 b of the air guide vanes 7 a-7 d.

In this embodiment, in order to support the air guide vanes 7 a-7 d of a pair of the airflow-direction changing apparatuses 6, 6 that are arranged laterally, the through-holes 4 b of the supporting member 4 are used in supporting the rotation shafts 9 b, however, a through-hole is not necessarily required to receive the rotation shafts 9 b of the air guide vanes 7 a-7 d. A hole or bore that can support the rotation shafts 9 b of the air guide vanes 7 a-7 d rotatably would be sufficient to receive the rotation shafts 9 b, regardless of the shape of a hole or bore.

In this embodiment, the rotation shafts 9 b of the air guide vanes 7 a-7 d are a column-shaped boss that projects from the inner end faces of the air guide vanes 7 a-7 d, and which are inserted into the through-holes 4 b of the supporting member 4. In another embodiment, it is possible to form a plurality of column-shaped bosses (not shown) in the supporting member 4 and insert the column-shaped bosses rotatably into holes (not shown) that are formed in the inside end faces of the air guide vanes 7 a-7 d. In addition, the air guide vanes 7 a-7 d are connected by a link member 10 to rotate in conjunction with one another.

As illustrated in FIGS. 2 and 4, the rotational vanes 8 a, 8 b, 8 c, 8 d, 8 e each have a rotation shaft 11 that extends in the vertical direction. The rotational vanes 8 a-8 e are disposed in the passages 1 a, 1 b of the air-conditioning duct 1, wherein the rotational vanes 8 a-8 e are placed at regular intervals and parallel to one another, and the rotational vanes 8 a-8 e are supported by the respective rotation shafts 11 to rotate in the horizontal direction C-C in FIG. 4. The rotation shafts 11 of the rotational vanes 8 a-8 e extend in parallel with the plane where the rotation shafts 9 a, 9 b of the air guide vanes 7 a-7 d are included and extend at an angle of 90 degrees with the rotation shafts 9 a, 9 b of the air guide vanes 7 a-7 d. The rotational vanes 8 a-8 e are connected by a link member 12 to rotate in conjunction with one another. In addition, the rotational vane 8 c is provided with an opening 13 and a link member 14 as illustrated in FIG. 2. The link member 14 is adjacent to the opening 13.

As illustrated in FIGS. 2, 4 and 6, an elastic member 15 is secured to the second air guide vane 7 b from the top in each airflow-direction changing apparatus 6. The elastic member 15 is filled in a projection 17 formed in the central region of the downstream edge 16 of the air guide vanes 7 b. The projection 17 extends from the downstream edge 16 of the air guide vane 17 b horizontally, so that the elastic member 15 fitted in the projection 17 extends from the downstream edge 16 of the air guide vane 17 b horizontally. The elastic member 15 may be made of rubber-based elastic materials such as silicone rubber.

An operation knob 18 is attached to the air guide vanes 7 b. As illustrated in FIGS. 2, 4 and 6, a recess 18 a for receiving an air guide vane is formed in the operation knob 18. In order to attach the operation knob 18 to the air guide vane 7 b, the air guide vane 7 b is inserted into the recess 18 a from the side of the downstream edge 16 of the air guide vane 7 b and thereby, a part of one surface of a wing profile of the air guide vane 7 b, a part of the other surface of the wing profile, a part of the downstream edge 16 of the air guide vane 7 b, and the elastic member 15 are disposed in the recess 18 a.

The operation knob 18 is fitted with a supporting rib 19, which sticks out in the recess 18 a and extends to the elastic member 15 so that the supporting rib 19 abuts on the elastic member 15 slidably. The operation knob 18 is also provided with a guide protrusion 18 b projecting into the recess 18 a, and the guide protrusion 18 b slidably engages with a groove 20 formed on the underside of the air guide vane 7 b. The groove 20 extends in the direction of reciprocation of the operation knob 18. Furthermore, the operation knob 18 is provided with a pair of claw portions 18 c, so that the claw portions 18 c slidably engage with the upstream edge 21 of the air guide vane 7 b. The operation knob 18 is fitted on the air guide vane 7 b by means of the supporting knob 19 abutting on the elastic member 15, the guide protrusion 18 b slidably engaging with the groove 20 of the air guide vane 7 b, and the pair of claw portions 18 c slidably engaging with the upstream edge 21 of the air guide vane 7 b and thereby, the operation knob 18 may slide in the wingspan direction B-B of the air guide vane 7 b. In addition, the operation knob 18 is provided with a pair of projection levers 18 d between which the link member 14 is pinched slidably and rotatably (refer to FIGS. 2 and 4).

The supporting member 4 is manufactured into a desired size and shape by a process of molding olefin-based thermoplastic elastomer having a hardness of between Shore A80 and Shore D60 in a molding die. The degree of mold transferability of olefin-based thermoplastic elastomer is characteristically lower than that of other thermoplastic elastomer. By virtue of molding olefin-based thermoplastic elastomer of such characteristics into the supporting member 4, a lot of microscopic concavities and convexities are formed not only on the molded surfaces of the supporting member 4 but also on the bearing surfaces for supporting the rotation shaft 9 b rotatably, regardless of how the working surfaces of the mold dies have been processed. The structure for supporting air guide vanes according to the present invention is characterized in that the rotation shaft 9 b formed on the inner end face of the air guide vane 7 b is rotatably borne by the supporting member 4 or the bearing surfaces on which such a lot of microscopic concavities and convexities are formed.

As illustrated in FIG. 4, the rotation shaft 9 a formed on the outside end face of the air guide vane 7 b is inserted into the hole 2 a of the panel member 2 and retained rotatably, wherein the rotation shaft 9 a is not borne by the supporting member 4 made of the aforementioned olefin-based thermoplastic elastomer, in this embodiment. In other words, the microscopic concavities and convexities of the supporting member 4 is not formed on the rotation shaft bearing surface of the hole 2 a of the panel member 2. When the air guide vane 7 b is rotated, a certain amount of load resistance to rotation is intentionally produced between the rotation shaft 9 b and the through-hole 4 b, while it is not intended to generate a particular load resistance to rotation between the rotation shaft 9 a and the hole 2 b. This is because a predetermined load resistance to rotation that will be produced by operation of the air guide vane 7 b can be adjusted by changing the degree of tightness between the rotation shaft 9 b and the through-hole 4 b. However, it is also within the scope of the present invention that a lot of microscopic concavities and convexities are formed not only on the rotation shaft bearing surface of the through-hole 4 b of the supporting member 4 but also on the rotation shaft bearing surface of the hole 2 a of the panel member 2, in order to produce a certain amount of load resistance to rotation not only between the rotation shaft 9 b and the through-hole 4 b but also between the rotation shaft 9 a and the hole 2 b, when the air guide vane 7 b is rotated.

FIG. 7 is a micrograph showing the surface of a molded article produced by the process of injecting a conventional polyester-based thermoplastic elastomer into a conventional mold die. On the other hand, FIG. 8 is a micrograph showing the surface of the supporting member 4 produced by the process of molding olefin-based thermoplastic elastomer according to the present invention. Comparing the micrograph of FIG. 7 with the micrograph of FIG. 8, it is found that a relatively large and extremely irregularly-dispersed concavities and convexities are formed on the surface of the molded article in FIG. 7 as a result that the irregular concavities and convexities formed on the working surface of the mold die are transferred to the surface of the molded article, while a lot of microscopic concavities and convexities are virtually uniformly dispersed on the surface of the molded article in FIG. 8.

As described above, a lot of microscopic convexities and concavities are virtually uniformly dispersed on the surface of the supporting member 4 and on the inner surface of the through-hole 4 b, that is, the rotation shaft bearing surface, in accordance with the present invention. As a result, the rotation shafts 9 b of the air guide vanes 7 a-7 d each are supported by so-called multiple point contacts with the inner surface of the respective through-holes 4 b. Consequently, the conventional load curve R1 shown in FIG. 9 represents a drastic change of the load resistance to rotation of an air guide vanes 7 a-7 d at peaks P1 and P2 when the air guide vanes 7 a-7 d are rotated around the rotation shafts 9 a, 9 b, while the load curve R2 according to the present invention represents a virtually constant load value at peaks P3 and P4 as shown in FIG. 10. In other words, by virtue of the supporting structure according to the present invention, wherein the rotation shafts 9 b of the air guide vanes 7 a-7 d are borne by the rotation shaft bearing surface of FIG. 8, the load curve R2 that indicates a change of load resistance to rotation of the air guide vanes 7 a-7 d with respect to a change of rotation angle of the air guide vanes 7 a-7 d does not represent a drastic change of load resistance at peaks P3 and P4.

When the air guide vanes 7 a-7 d are rotated by holding the operation knob 18, the drastic changes of load resistance to rotation generated at peaks P1 and P2 in FIG. 9 make the operational feeling of the operation knob 18 worse in a conventional structure, however, there is no abrupt change of load in peaks P3 and P4 of the torque in the present invention, as shown in FIG. 10. Consequently, in accordance with the present invention, a constant operational feeling of the operation knob 18 can be obtained when rotating the air guide vanes 7 a-7 d.

The function of the above-mentioned apparatus 6 for changing the direction of airflow is briefly described as follows. The controlled-air that flows down in the direction of A in FIG. 2 passes through the rotational vanes 8 a-8 e and the air guide vanes 7 a-7 d, then runs out of two supply openings 3 a, 3 b. As the operation knob 18 is turned upwardly or downwardly, the air guide vanes 7 a-7 d are turned upwardly or downwardly and retained at a desired angle. In addition, as the operation knob 18 is slid in the wingspan direction B-B, the lever member 18 d of the operation knob 18 turns the link member 14 of the rotating vane 8 c, so that the rotational vanes 8 a-8 d are rotated horizontally and retained at a desired angle. Consequently, the direction of airflow flowing out of two supply openings 3 a, 3 b can be changed at any angle, separately.

In the embodiment described above, the structure for supporting air guide vanes according to the present invention is applied to a supply opening for air conditioning that opens to a vehicle inside, however, the structure can be also applied to a supply opening of household or professional-use air blowers without substantial modification. 

1. A structure for supporting an air guide vane in a supply opening for air conditioning, the structure comprising: an air guide vane disposed in a supply opening and manually rotatable to change direction of airflow; and a supporting member having a bearing surface supporting the air guide vane and microscopic concavities and convexities on the bearing surface to control resistance to rotation of the air guide vane.
 2. The structure as recited in claim 1, wherein the microscopic concavities and convexities on the bearing surface maintain a peak value of torque required to rotated the air guide vane at a substantially constant value during rotation of the air guide vanes.
 3. The structure as recited in claim 1, wherein the microscopic concavities and convexities avoid an abrupt change in torque required to rotate the air guide vane when the torque is a peak value.
 4. The structure as recited in claim 1, including a rotation shaft on an end face of the air guide vane, and a hole receiving the rotation shaft in the supporting member, wherein the microscopic concavities and convexities are located one an inner surface of the hole, and the rotation shaft is supported by multiple point contacts with the inner surface of the hole, provided by the microscopic concavities and convexities.
 5. The structure as recited in claim 4, wherein the rotation shaft of the air guide vane includes a circular column-shaped boss, wherein the hole receives the circular column-shaped boss rotatably, and the inner surface of the hole provides the bearing surface.
 6. The structure as recited in claim 1, wherein the supporting member is formed by die molding of an olefin-based thermoplastic elastomer, and the microscopic concavities and convexities are formed at least on the bearing surface supporting the air guide vanes rotatably in the die molding.
 7. The structure as recited in claim 6, wherein the olefin-based thermoplastic elastomer has a hardness in a range from Shore A80 to Shore D60.
 8. The structure as recited in claim 1, including: first and second circular column-shaped bosses that comprise a rotation shaft of the air guide vane, located in inner and outer end faces of the air guide vane, respectively; and a hole receiving the circular column-shaped boss rotatably in the supporting member; a bearing surface supporting the first circular column-shaped boss located in an inner surface of the hole, wherein the first circular column-shaped boss of the air guide vane is inserted into the hole of the supporting member and the second circular column-shaped boss is supported to rotate freely to avoid varying torque required to rotate the air guide vane.
 9. The structure as recited in claim 8, wherein: the air guide vane consists of a set of air guide vanes that are arranged to move from a predetermined space between adjacent air guide vanes and to extend parallel to one another; and the supporting member includes a plurality of the holes; the first of the circular column-shaped bosses of each of said air guide vanes are inserted into respective holes; and further including a link member connecting the air guide vanes to rotate in conjunction with one another; and an operation knob attached to one of the air guide vanes.
 10. The structure as recited in claim 10, including: first and second sets of the air guide vanes located on opposite sides of the supporting member; a plurality of through-holes located at predetermined intervals in the supporting member, wherein the circular column-shaped bosses on the inner end faces of the air guide vanes are rotatably inserted into respective through-holes from opposite sides of the supporting member.
 11. The structure as recited in claim 9, including a plurality of rotational vanes arranged on an upstream side of the first set of air guide vanes, wherein the rotational vanes are located at a regular interval and are parallel to one another; a link member connecting the rotational vanes to rotate in conjunction with one another; and an operation knob attached to the air guide vane and reciprocating in a wingspan direction of the air guide vane, wherein the rotational vanes are rotated by moving the operation knob in the wingspan direction of the air guide vane. 